The present application relates to the art of deactivating biological and chemical warfare agents. It finds particular application in conjunction with G-type, V-type, and H-type nerve agents, as well as biological agents.
Chemical warfare agents include G-type, V-type, and H-type agents. G-type agents are phosphor containing and are clear, colorless, and tasteless liquids that are miscible in water and most organic solvents. Examples include ethyl-N, N dimethyl phosphoramino cyanidate (Tabun or agent GA), phosphonofluoridate esters, such as isopropyl methyl phosphonofluoridate (Sarin or Agent GB), and methylphosphonofluoridic acid 1,2,2-trimethylpropyl ester (Soman or Agent GD). GB is odorless and is the most volatile nerve agent, evaporating at about the same rate as water. GA has a slightly fruity odor, and GD has a slight camphor-like odor. H-type agents include di(2-chloroethyl) sulfide (mustard gas or Agent HD) and dichloro(2-chlorovinyl)arsine (Lewisite).
V-type nerve agents contain a substituted amine group, and include methyl phosphonothiolates having an internal amino group. Examples include o-ethyl-S-(2-diisopropyl aminoethyl) methyl phosphono-thiolate (agent VX), O-isobutyl-S-(2-diethyl) ethyl methylphosphonothiolate, and O,S-diethyl methylphosphonothiolate. The phosphonothiolates form toxic hydrolysis products comprising phosphonothioic acids. VX is a clear, amber-colored, odorless, oily liquid. It is miscible with water and soluble in all solvents. It is the least volatile nerve agent.
Liquid oxidants have been developed which can deactivate biological warfare agents. See, for example, U.S. Pat. No. 6,245,957 to Wagner, et al. In Wagner, a strong oxidant solution is sprayed as a liquid onto equipment in the field which is or has potentially been contaminated with biological or chemical warfare agents. After treatment, the solution is rinsed from the equipment with water which can be permitted to flow onto the ground as non-toxic waste. Although effective, the liquid Wagner solution has drawbacks. First, it is difficult for liquids to penetrate crevices, fine cracks, ducts, and partially protected or overlapping parts. Second, in enclosed spaces such as the interior of airplanes, tanks, and buildings, cleanup and disposal of the liquid solution can be problematic. Third, liquids can damage some equipment, such as electronic or electrical equipment.
Blistering agents, such as HD (sulfur mustard) undergo oxidation to non-vesicating products (sulfide to sulfoxide). With the correct choice of agents, the further oxidation to the sulfone does not occur. This is preferable as both the sulfide and the sulfone have vesicant properties; whereas, the sulfoxide is non-vesicant.
Peroxide causes a perhydrolysis reaction neutralizing V-type nerve agents, such as VX nerve agent. In the perhydrolysis reaction, the peroxide moiety substitutes one of the groups around the phosphorous atom at the active site of the nerve agent molecule. Perhydrolysis is more effective against V-type nerve agents than base catalyzed hydrolysis by water. In the presence of water, such as a water and ammonia wash, the base catalyzed hydrolysis reaction can form EA2192 which is also highly toxic. EA2192 is a phosphonothioic acid which has the same basic structure as VX except that the terminal ethoxy group is replaced with OH.
On the other hand, G-agents, such as GD tend to be quite stable in the presence of hydrogen peroxide. GD does not undergo an autocatalytic perhydrolysis neutralizing reaction with hydrogen peroxide. Rather, G-type agents are typically deactivated with liquid hydrogen peroxide by base catalysis. Specifically, ammonia has been used to facilitate the base catalyzed hydrolysis of agents with liquid hydrogen peroxide, or perhydrolysis. Molybdate ions have also been used in combination with liquid hydrogen peroxide. The permolybdate ions formed have been found to deactivate G, V and H-agents.
The present application delivers a vapor phase deactivator which is effective against G, V, and H-type agents, as well as against biological agents.